Prince Amukamara -- I Wasn't the Only Giant ... at NYC Bar Mitzvah Bash!

Apparently, Bar Mitzvahs are a team sport in New York City ... because NY Giants star Prince Amukamara was with a bunch of other G-Men when he turnt up with the Hebrews ... TMZ Sports has learned.

Prince -- along with fellow Giants players Walter Thurmond (CB), Henry Hynoski (FB) Michael Cox (RB) ... and former Giants stars Ahmad Bradshaw, Ottis Anderson (RB) and Stephen Baker (WR) -- helped a kid named A.J. celebrate his journey into manhood this past weekend.

Prince tells us the whole thing was put together by Tiki Barber -- who runs Thuzio ... a company that allows people to to hire stars to appear at cool functions ... like Bar Mitzvahs.

"It really was a big surprise for the boy A.J.," Prince said ... "They announced us ... they had our pictures, it was pretty great. I'm sure the kids had a great time, and so did I!!"

Prince says he had a blast at the party -- "The dancing was my favorite part. There was an MC. They had professional dancers. Hynoski said he was dancing before I got there. We did all do the 'Cha Cha Slide' together."